JP5630152B2 - Waste liquid treatment equipment - Google Patents

Description

  The present invention relates to a waste liquid treatment apparatus.

  Conventionally, methods such as incineration and biological treatment are known as methods for treating waste liquid. However, the incineration process has a problem that energy and chemicals are required in the pretreatment dehydration and solid content aggregation, and dioxins are generated due to incomplete combustion. In addition, the biological treatment has a problem that the treatment time is long and the activated sludge generated after the treatment becomes a new waste.

  Therefore, a method for treating a waste liquid in hot water such as subcritical water, superheated steam, or supercritical water is known.

  Patent Document 1 discloses a PCB processing method for detoxifying PCB contained in power equipment such as a power transformer and a capacitor. This PCB processing method includes a step of dividing and crushing components of power equipment such as a power transformer or a capacitor, and organic waste such as paper, wood or resin contaminated by PCB from the divided and crushed pieces. A step of separating the material from the material and a step of hydrothermal decomposition or supercritical water oxidation of the extracted organic waste.

  On the other hand, a reactor for hydrothermal decomposition treatment or supercritical water oxidation treatment of organic waste is required to have corrosion resistance.

  Patent Document 2 discloses a method of manufacturing a double tube in which an inner tube is inserted inside an outer tube and the outer tube and the inner tube are overlapped and joined. At this time, the material of the outer tube is carbon steel, low alloy steel or austenitic stainless steel, and the material of the inner tube is Ti or Zr having a smaller thermal expansion coefficient than the material of the outer tube.

  However, when the organic waste is applied to a reactor for hydrothermal decomposition treatment or supercritical water oxidation treatment, there is a problem that steam leaks.

  An object of the present invention is to provide a waste liquid treatment apparatus capable of suppressing steam leakage even when water is changed to subcritical water, superheated steam or supercritical water. And

The invention according to claim 1 is a waste liquid treatment apparatus for treating a waste liquid containing water and organic matter, wherein the water is changed to subcritical water, superheated steam or supercritical water, and the organic matter is oxidized. A waste liquid supply means for supplying the waste liquid to the reactor, an oxidant supply means for supplying an oxidant to the reactor, and a heating means for heating the reactor, wherein the reactor has an outer tube And the inner tube and the outer tube and the inner tube have linear expansion coefficients at 25 ° C. of α ₁ [° C. ⁻¹ ] and α ₂ [° C. ⁻¹ ] , respectively, and the heating means. Assuming that the temperature inside the reactor heated by T is T [° C.] , the formula α ₁ <α ₂
0 <(α ₂ −α ₁ ) × (T−25) ≦ 2 × 10 ⁻³
Meets the reactor, on the side where the waste liquid side and the organic material is oxidized liquid waste is supplied is discharged, further comprising a joint member, said heating means, not to heat the joint member Features.

  According to a second aspect of the present invention, in the waste liquid treatment apparatus according to the first aspect, the inner tube includes titanium, tantalum, a titanium-palladium alloy, or a nickel alloy.

  According to a third aspect of the present invention, in the waste liquid treatment apparatus according to the first or second aspect, the outer tube and the inner tube are joined by diffusion joining or brazing.

According to a fourth aspect of the present invention, in the waste liquid treatment apparatus according to any one of the first to third aspects, the reactor further includes a heat insulating member that insulates the joint member.

  ADVANTAGE OF THE INVENTION According to this invention, even if it changes water into subcritical water, superheated steam, or supercritical water, the waste liquid processing apparatus which can suppress a leak of a steam can be provided.

It is a figure which shows an example of the waste liquid processing apparatus of this invention. It is sectional drawing which shows the reactor of FIG. It is the elements on larger scale of the waste liquid processing apparatus of FIG.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows an example of the waste liquid treatment apparatus of the present invention. The waste liquid treatment apparatus 100 for treating the waste liquid 21a containing water and organic matter changes the water into subcritical water, superheated steam or supercritical water, and supplies the waste liquid 21a to the reactor 10 for oxidizing the organic matter. A waste liquid supply unit 20, an air supply unit 30 for supplying air to the reactor 10, a waste liquid 21 a supplied to the reactor 10 and a preheater 40 for preheating the air, a heater 50 for heating the reactor 10, It has a heat exchanger 60 for exchanging heat with the waste liquid oxidized from the organic matter discharged from the reactor 10, and a gas-liquid separation unit 70 for gas-liquid separation of the waste liquid oxidized from the organic matter discharged from the reactor 10.

As shown in FIGS. 2 and 3, the reactor 10 includes a side where the waste liquid 21 a of the double pipe 11 where the outer pipe 11 a and the inner pipe 11 b are joined and a side where the waste liquid where organic matter is oxidized is discharged. In addition, joint members 12A and 12B are respectively installed. Further, MnO ₂ (not shown) is filled as an oxidation catalyst in the vicinity of the end portion on the side where the waste liquid in which the organic matter in the double pipe 11 is oxidized is discharged. At this time, since the heater 50 is installed on the outer surface of the double pipe 11 and is installed so as not to heat the joint members 12A and 12B, the durability of the joint members 12A and 12B can be improved.

  Furthermore, since glass wool 13A and 13B are installed in the joint members 12A and 12B, the temperature inside the reactor 10 can be made uniform.

  Note that heat insulating members such as rock wool, foamed glass, phenol foam, and cellulose fiber may be used instead of the glass wool 13A and 13B.

  Further, if the organic matter contained in the waste liquid 21a can be sufficiently oxidized without insulating the joint members 12A and 12B, the glass wool 13A and 13B need not be installed.

  The temperature inside the reactor 10 is detected by the temperature sensor T, and the heater 50 is controlled so as to reach a predetermined temperature.

At this time, if the linear expansion coefficients at 25 ° C. of the outer tube 11a and the inner tube 11b are α ₁ and α ₂ , respectively, and the temperature inside the reactor 10 heated by the heater 50 is T, the equation α ₁ <α ₂
Is satisfied, and the formula (α ₂ −α ₁ ) × (T−25) (1)
Is 0 to 2 × 10 ⁻³ , and preferably 5 × 10 ^{−4 to} 1.5 × 10 ⁻³ . When the value of the formula (1) is 0 or less or exceeds 2 × 10 ⁻³ , if the water is changed to subcritical water, superheated steam or supercritical water, the outer tube 11a and the inner tube 11b may be shifted. , Peeling or vapor leaks.

  The temperature T inside the reactor 10 heated by the heater 50 is usually 100 to 700 ° C, preferably 200 to 600 ° C.

  The material constituting the outer tube 11a is not particularly limited as long as it is a material excellent in heat resistance and pressure resistance, and examples thereof include Kovar alloy, low thermal expansion super heat resistant alloy HRA929 (manufactured by Hitachi Metals) and the like.

  The material constituting the inner tube 11b is not particularly limited as long as it is a material excellent in heat resistance and corrosion resistance, and examples thereof include titanium, tantalum, titanium / palladium alloy, and nickel alloy.

  A method for joining the outer tube 11a and the inner tube 11b is not particularly limited, and examples thereof include welding joining and solid phase joining. Among these, diffusion bonding and brazing are preferable because of excellent durability.

  A method for joining the outer tube 11a and the inner tube 11b by diffusion bonding is not particularly limited, and examples thereof include hot isostatic pressing (HIP).

  The difference between the inner diameter of the outer tube 11a and the outer diameter of the inner tube 11b is usually 3 to 15 mm, preferably 5 to 10 mm. If the difference between the inner diameter of the outer tube 11a and the outer diameter of the inner tube 11b is less than 3 mm, it may be difficult to insert the inner tube 11b into the outer tube 11a. If the difference exceeds 15 mm, the outer tube 11a and the inner tube 11b May be difficult to join.

  Although it does not specifically limit as the heater 50, A rubber heater, a band heater, a ceramic heater, a halogen heater, a sheathed heater, an oil heater etc. are mentioned.

The waste liquid supply unit 20 includes a tank 21 in which the waste liquid 21 a is stored, a pump 22 that compresses the waste liquid 21 a and continuously supplies the waste liquid 21 a to the reactor 10, and an on-off valve 23. At this time, the stirring blade 21b is installed in the tank 21, and the waste liquid 21a can be stirred. The pressure of the waste liquid 21a to be supplied to the reactor 10 is detected by the pressure sensor P _1, the pump 22 is controlled to a predetermined pressure.

  The pressure of the waste liquid 21a supplied to the reactor 10 is usually 1 to 50 MPa, and preferably 5 to 35 MPa.

The air supply unit 30 includes a compressor 31 that compresses air to a pressure equal to or higher than the pressure at which the waste liquid is supplied and continuously supplies the compressed air to the reactor 10, and an on-off valve 32. At this time, the pressure of the air supplied to the reactor 10 is detected by the pressure sensor P _2, the compressor 31 to a predetermined pressure is controlled.

As described above, in the reactor 10, the waste liquid 21 a supplied from the waste liquid supply unit 20 and the air introduced from the air supply unit 30 are mixed. At this time, the waste liquid 21 a and air are preheated by the preheater 40. Next, it is heated by the heater 50, and the water contained in the waste liquid 21a is changed to subcritical water, superheated steam or supercritical water, and the organic matter contained in the waste liquid 21a is oxidized and reduced in molecular weight. Furthermore, the organic substance reduced in molecular weight is completely oxidized by the catalytic action of MnO ₂ .

  Since the water 61 is stored in the heat exchanger 60, the waste liquid obtained by oxidizing the organic matter discharged from the reactor 10 exchanges heat with the water 61 to generate water vapor.

  The gas-liquid separation unit 70 includes a back pressure valve 71 that depressurizes the waste liquid that has been oxidized by the organic matter discharged from the heat exchanger 60 to atmospheric pressure, and a gas-liquid separator 72 that gas-liquid separates the waste liquid that has been oxidized by the depressurized organic substance. Have. At this time, the gas-liquid separator 72 separates the waste liquid obtained by oxidizing the reduced-pressure organic matter into water containing a slight amount of inorganic acid, etc., and a gas containing carbon dioxide gas, nitrogen gas, etc. Contained water is recovered. Water that contains a small amount of inorganic acid or the like is reused as industrial water after confirming water quality standards.

In place of MnO ₂ , Pt, Ir, Ag, Pd, Rh, Ru, Cu, Ni, Co, Fe, W, PdO, PtO, PtO ₂ , Ag ₂ O, RuO ₂ , CuO, Co ₃ O ₄ NiO, Fe ₂ O ₃ , V ₂ O 5, Cr ₂ O ₃ , CdO, CeO ₂ , Al ₂ O ₃ , ThO _2, or the like may be used.

  Further, instead of the air supply unit 30 for supplying air to the reactor 10, an ozone supply unit for supplying ozone to the reactor 10, a hydrogen peroxide solution supply unit for supplying hydrogen peroxide solution to the reactor 10, etc. are used. May be.

  Hereinafter, the present invention will be specifically described based on examples.

[Example 1]
A tube made of Kovar alloy having an outer diameter of 12.7 mm, a thickness of 1.24 mm, a length of 600 mm, and a linear expansion coefficient α _{1 at} 25 ° C. of 5.0 × 10 ⁻⁶ ° C. ⁻¹ as the outer tube 11a. And a tube made of tantalum having an outer diameter of 10 mm, a thickness of 0.5 mm, a length of 600 mm, and a linear expansion coefficient α _{2 at} 25 ° C. of 6.3 × 10 ⁻⁶ ° C. ⁻¹ as the inner pipe 11b. The double tube 11 was obtained by mounting on a standard small HIP device, diffusion-bonding by HIP treatment at 1000 ° C. and 90 MPa for 1 hour.

Using the waste liquid treatment apparatus 100 in which the obtained double pipe 11 was installed, an 8 mass% aqueous methanol solution was treated. At this time, 5 g of MnO ₂ was filled in the vicinity of the end portion on the side where the waste liquid in which the organic matter in the double pipe 11 was oxidized was discharged.

First, the reactor 10 was heated using the heater 50 with the on-off valves 23 and 32 closed. At this time, since the temperature T inside the reactor 10 heated by the heater 50 is 410 ° C., the waste liquid treatment apparatus 100 has a value of Equation (1) of 5.0 × 10 ⁻⁴ (see Table 1). ).

  Next, the on-off valves 23 and 32 are opened, and an 8 mass% aqueous methanol solution is supplied to the reactor 10 at 10 MPa using the pump 22, and air is supplied to the reactor 10 at 10.5 MPa using the compressor 31. did. At this time, the residence time of the 8 mass% methanol aqueous solution in the reactor 10 was set to 1 minute.

  Next, the waste liquid in which the organic matter discharged from the reactor 10 was oxidized was instantaneously cooled to 25 ° C. by exchanging heat with the water 61 stored in the heat exchanger 60. Further, the waste liquid in which the cooled organic matter was oxidized was decompressed by the back pressure valve 71 and then separated into a liquid component and a gas component by the gas-liquid separator 72.

  When the liquid component and the gas component separated by the gas-liquid separator 72 were analyzed, it was found that a 99.999% decomposition rate was achieved on the TOC basis, the liquid component contained water, and the gas component was carbon dioxide. And water were confirmed.

  Further, the steam did not leak from the joint members 12A and 12B.

[Example 2]
As the outer tube 11a, a low thermal expansion super heat resistant alloy HRA929 having an outer diameter of 12.7 mm, a thickness of 1.24 mm, a length of 600 mm, and a linear expansion coefficient α _{1 at} 25 ° C. of 6.0 × 10 ⁻⁶ ° C. ^−1. A double tube 11 was obtained in the same manner as in Example 1 except that a tube made by Hitachi Metals was used.

An 8% by mass aqueous methanol solution was treated in the same manner as in Example 1 except that the waste liquid treatment apparatus 100 in which the obtained double pipe 11 was installed was used. At this time, the value of the formula (1) is 1.2 × 10 ⁻⁴ (see Table 1).

  When the liquid component and the gas component separated by the gas-liquid separator 72 were analyzed, it was found that a 99.999% decomposition rate was achieved on the TOC basis, the liquid component contained water, and the gas component was carbon dioxide. And water were confirmed.

  Further, the steam did not leak from the joint members 12A and 12B.

[Example 3]
As the inner tube 11b, a titanium tube having an outer diameter of 10 mm, a thickness of 0.5 mm, a length of 600 mm, and a linear expansion coefficient α _{2 at} 25 ° C. of 8.5 × 10 ⁻⁶ ° C. ⁻¹ was used. Obtained a double tube 11 in the same manner as in Example 2.

An 8% by mass aqueous methanol solution was treated in the same manner as in Example 1 except that the waste liquid treatment apparatus 100 in which the obtained double pipe 11 was installed was used. At this time, the value of Formula (1) is 9.6 × 10 ⁻⁴ (see Table 1).

  When the liquid component and the gas component separated by the gas-liquid separator 72 were analyzed, it was found that a 99.999% decomposition rate was achieved on the TOC basis, the liquid component contained water, and the gas component was carbon dioxide. And water were confirmed.

  Further, the steam did not leak from the joint members 12A and 12B.

[Example 4]
A double tube 11 was obtained in the same manner as in Example 2 except that Cu was used as the brazing material and the outer tube and the inner tube were joined by brazing.

An 8% by mass aqueous methanol solution was treated in the same manner as in Example 1 except that the waste liquid treatment apparatus 100 in which the obtained double pipe 11 was installed was used. At this time, the value of the formula (1) is 1.2 × 10 ⁻⁴ (see Table 1).

  When the liquid component and the gas component separated by the gas-liquid separator 72 were analyzed, it was found that a 99.999% decomposition rate was achieved on the TOC basis, the liquid component contained water, and the gas component was carbon dioxide. And water were confirmed.

  Further, the steam did not leak from the joint members 12A and 12B.

[Comparative Example 1]
As the outer tube 11a, a tube made of SUS316 having an outer diameter of 12.7 mm, a thickness of 1.24 mm, a length of 600 mm, and a linear expansion coefficient α _{1 at} 25 ° C. of 1.6 × 10 ⁻⁵ ° C. ⁻¹ is used. A double tube 11 was obtained in the same manner as in Example 1 except that.

An 8% by mass aqueous methanol solution was treated in the same manner as in Example 1 except that the waste liquid treatment apparatus 100 in which the obtained double pipe 11 was installed was used. At this time, the value of the formula (1) is −3.7 × 10 ⁻³ (see Table 1).

As a result, when the pressure sensor _{P 1} becomes 3 MPa, rapid drop in pressure, the steam from the joint members 12A and 12B are leaked. As a result of scrutinizing the double pipe 11, the outer pipe 11a was relatively expanded at the end face as compared with the inner pipe 11b, and the sealing performance was lowered.

[Comparative Example 2]
As the inner tube, a tube made of titanium having an outer diameter of 10 mm, a thickness of 0.5 mm, a length of 600 mm, and a linear expansion coefficient α _{2 at} 25 ° C. of 8.5 × 10 ⁻⁶ ° C. ⁻¹ was used. In the same manner as in Comparative Example 1, a double tube 11 was obtained.

An 8% by mass aqueous methanol solution was treated in the same manner as in Example 1 except that the waste liquid treatment apparatus 100 in which the obtained double pipe 11 was installed was used. At this time, the value of the equation (1) is −2.9 × 10 ⁻³ (see Table 1).

As a result, when the pressure sensor _{P 1} becomes 2 MPa, rapid drop in pressure, the steam from the joint members 12A and 12B are leaked. As a result of scrutinizing the double pipe 11, the outer pipe 11a was relatively expanded at the end face as compared with the inner pipe 11b, and the sealing performance was lowered.

[Comparative Example 3]
As the outer tube 11a, a titanium tube having an outer diameter of 12.7 mm, a thickness of 1.24 mm, a length of 600 mm, and a linear expansion coefficient α _{1 at} 25 ° C. of 8.5 × 10 ⁻⁶ ° C.− ¹ , As the tube 11b, a tube made of SUS316 having an outer diameter of 10 mm, a thickness of 0.5 mm, a length of 600 mm, and a linear expansion coefficient α _{2 at} 25 ° C. of 1.6 × 10 ⁻⁵ ° C. ⁻¹ was used. In the same manner as in Example 4, a double tube 11 was obtained.

An 8% by mass aqueous methanol solution was treated in the same manner as in Example 1 except that the waste liquid treatment apparatus 100 in which the obtained double pipe 11 was installed was used. At this time, the value of Formula (1) is 2.9 × 10 ⁻³ (see Table 1).

  As a result, the outer tube 11a was destroyed by the stress of the inner tube 11b, and the steam leaked.

  Table 1 shows the evaluation results.

表１から、実施例１〜４の廃液浄化装置１００は、式（１）の値が０〜２×１０^−３であるため、蒸気のリークを抑制できることがわかる。

From Table 1, it turns out that the waste liquid purification apparatus 100 of Examples 1-4 can suppress the leak of a vapor | steam since the value of Formula (1) is 0-2 * 10 < ^-3 >.

  On the other hand, in the waste liquid purification apparatuses 100 of Comparative Examples 1 and 2, since the value of the formula (1) was 0 or less, the steam leaked.

Moreover, since the value of Formula (1) exceeded 2 * 10 < ^-3 >, the waste liquid purification apparatus 100 of the comparative example 3 leaked the vapor | steam.

DESCRIPTION OF SYMBOLS 100 Waste liquid processing apparatus 10 Reactor 11 Double pipe 11a Outer pipe 11b Inner pipe 12A, 12B Joint member 13A, 13B Glass wool 20 Waste liquid supply part 21 Tank 21a Waste liquid 21b Stirring blade 22 Pump 23 Open / close valve 30 Air supply part 31 Compressor 32 Open / close Valve 40 Preheater 50 Heater 60 Heat exchanger 61 Water 70 Gas-liquid separator 71 Back pressure valve 72 Gas-liquid separator T Temperature sensor P ₁ , P ₂ Pressure sensor

JP 2002-143825 A Japanese Patent Laid-Open No. 63-165028

Claims (4)

A waste liquid treatment apparatus for treating a waste liquid containing water and organic matter,
A reactor for changing the water to subcritical water, superheated steam or supercritical water, and oxidizing the organic matter;
Waste liquid supply means for supplying the waste liquid to the reactor;
An oxidant supply means for supplying an oxidant to the reactor;
Heating means for heating the reactor;
The reactor has a double pipe in which an outer pipe and an inner pipe are joined,
The linear expansion coefficients of the outer tube and the inner tube at 25 ° C. are α ₁ [° C. ⁻¹ ] and α ₂ [° C. ⁻¹ ] , respectively, and the temperature inside the reactor heated by the heating means is T [° C. ] , The formula α ₁ <α ₂
0 <(α ₂ −α ₁ ) × (T−25) ≦ 2 × 10 ⁻³
Meet the,
The reactor further has a joint member on the side where the waste liquid is supplied and the side where the waste liquid where the organic matter is oxidized is discharged,
The waste liquid treatment apparatus , wherein the heating means does not heat the joint member .   The waste liquid treatment apparatus according to claim 1, wherein the inner tube contains titanium, tantalum, titanium-palladium alloy, or nickel alloy.   The waste liquid treatment apparatus according to claim 1 or 2, wherein the outer pipe and the inner pipe are joined by diffusion joining or brazing. The waste liquid treatment apparatus according to any one of claims 1 to 3, wherein the reactor further includes a heat insulating member for heat insulating the joint member.

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